commit.c

   1 #include "cache.h"
   2 #include "tag.h"
   3 #include "commit.h"
   4 #include "commit-graph.h"
   5 #include "repository.h"
   6 #include "object-store.h"
   7 #include "pkt-line.h"
   8 #include "utf8.h"
   9 #include "diff.h"
  10 #include "revision.h"
  11 #include "notes.h"
  12 #include "alloc.h"
  13 #include "gpg-interface.h"
  14 #include "mergesort.h"
  15 #include "commit-slab.h"
  16 #include "prio-queue.h"
  17 #include "hash-lookup.h"
  18 #include "wt-status.h"
  19 #include "advice.h"
  20 #include "refs.h"
  21 #include "commit-reach.h"
  22 #include "run-command.h"
  23 #include "shallow.h"
  24 #include "hook.h"
  25
  26 static struct commit_extra_header *read_commit_extra_header_lines(const char *buf, size_t len, const char **);
  27
  28 int save_commit_buffer = 1;
  29 int no_graft_file_deprecated_advice;
  30
  31 const char *commit_type = "commit";
  32
  33 struct commit *lookup_commit_reference_gently(struct repository *r,
  34                 const struct object_id *oid, int quiet)
  35 {
  36         struct object *obj = deref_tag(r,
  37                                        parse_object(r, oid),
  38                                        NULL, 0);
  39
  40         if (!obj)
  41                 return NULL;
  42         return object_as_type(obj, OBJ_COMMIT, quiet);
  43 }
  44
  45 struct commit *lookup_commit_reference(struct repository *r, const struct object_id *oid)
  46 {
  47         return lookup_commit_reference_gently(r, oid, 0);
  48 }
  49
  50 struct commit *lookup_commit_or_die(const struct object_id *oid, const char *ref_name)
  51 {
  52         struct commit *c = lookup_commit_reference(the_repository, oid);
  53         if (!c)
  54                 die(_("could not parse %s"), ref_name);
  55         if (!oideq(oid, &c->object.oid)) {
  56                 warning(_("%s %s is not a commit!"),
  57                         ref_name, oid_to_hex(oid));
  58         }
  59         return c;
  60 }
  61
  62 struct commit *lookup_commit(struct repository *r, const struct object_id *oid)
  63 {
  64         struct object *obj = lookup_object(r, oid);
  65         if (!obj)
  66                 return create_object(r, oid, alloc_commit_node(r));
  67         return object_as_type(obj, OBJ_COMMIT, 0);
  68 }
  69
  70 struct commit *lookup_commit_reference_by_name(const char *name)
  71 {
  72         struct object_id oid;
  73         struct commit *commit;
  74
  75         if (get_oid_committish(name, &oid))
  76                 return NULL;
  77         commit = lookup_commit_reference(the_repository, &oid);
  78         if (parse_commit(commit))
  79                 return NULL;
  80         return commit;
  81 }
  82
  83 static timestamp_t parse_commit_date(const char *buf, const char *tail)
  84 {
  85         const char *dateptr;
  86
  87         if (buf + 6 >= tail)
  88                 return 0;
  89         if (memcmp(buf, "author", 6))
  90                 return 0;
  91         while (buf < tail && *buf++ != '\n')
  92                 /* nada */;
  93         if (buf + 9 >= tail)
  94                 return 0;
  95         if (memcmp(buf, "committer", 9))
  96                 return 0;
  97         while (buf < tail && *buf++ != '>')
  98                 /* nada */;
  99         if (buf >= tail)
 100                 return 0;
 101         dateptr = buf;
 102         while (buf < tail && *buf++ != '\n')
 103                 /* nada */;
 104         if (buf >= tail)
 105                 return 0;
 106         /* dateptr < buf && buf[-1] == '\n', so parsing will stop at buf-1 */
 107         return parse_timestamp(dateptr, NULL, 10);
 108 }
 109
 110 static const struct object_id *commit_graft_oid_access(size_t index, const void *table)
 111 {
 112         const struct commit_graft * const *commit_graft_table = table;
 113         return &commit_graft_table[index]->oid;
 114 }
 115
 116 int commit_graft_pos(struct repository *r, const struct object_id *oid)
 117 {
 118         return oid_pos(oid, r->parsed_objects->grafts,
 119                        r->parsed_objects->grafts_nr,
 120                        commit_graft_oid_access);
 121 }
 122
 123 int register_commit_graft(struct repository *r, struct commit_graft *graft,
 124                           int ignore_dups)
 125 {
 126         int pos = commit_graft_pos(r, &graft->oid);
 127
 128         if (0 <= pos) {
 129                 if (ignore_dups)
 130                         free(graft);
 131                 else {
 132                         free(r->parsed_objects->grafts[pos]);
 133                         r->parsed_objects->grafts[pos] = graft;
 134                 }
 135                 return 1;
 136         }
 137         pos = -pos - 1;
 138         ALLOC_GROW(r->parsed_objects->grafts,
 139                    r->parsed_objects->grafts_nr + 1,
 140                    r->parsed_objects->grafts_alloc);
 141         r->parsed_objects->grafts_nr++;
 142         if (pos < r->parsed_objects->grafts_nr)
 143                 memmove(r->parsed_objects->grafts + pos + 1,
 144                         r->parsed_objects->grafts + pos,
 145                         (r->parsed_objects->grafts_nr - pos - 1) *
 146                         sizeof(*r->parsed_objects->grafts));
 147         r->parsed_objects->grafts[pos] = graft;
 148         return 0;
 149 }
 150
 151 struct commit_graft *read_graft_line(struct strbuf *line)
 152 {
 153         /* The format is just "Commit Parent1 Parent2 ...\n" */
 154         int i, phase;
 155         const char *tail = NULL;
 156         struct commit_graft *graft = NULL;
 157         struct object_id dummy_oid, *oid;
 158
 159         strbuf_rtrim(line);
 160         if (!line->len || line->buf[0] == '#')
 161                 return NULL;
 162         /*
 163          * phase 0 verifies line, counts hashes in line and allocates graft
 164          * phase 1 fills graft
 165          */
 166         for (phase = 0; phase < 2; phase++) {
 167                 oid = graft ? &graft->oid : &dummy_oid;
 168                 if (parse_oid_hex(line->buf, oid, &tail))
 169                         goto bad_graft_data;
 170                 for (i = 0; *tail != '\0'; i++) {
 171                         oid = graft ? &graft->parent[i] : &dummy_oid;
 172                         if (!isspace(*tail++) || parse_oid_hex(tail, oid, &tail))
 173                                 goto bad_graft_data;
 174                 }
 175                 if (!graft) {
 176                         graft = xmalloc(st_add(sizeof(*graft),
 177                                                st_mult(sizeof(struct object_id), i)));
 178                         graft->nr_parent = i;
 179                 }
 180         }
 181         return graft;
 182
 183 bad_graft_data:
 184         error("bad graft data: %s", line->buf);
 185         assert(!graft);
 186         return NULL;
 187 }
 188
 189 static int read_graft_file(struct repository *r, const char *graft_file)
 190 {
 191         FILE *fp = fopen_or_warn(graft_file, "r");
 192         struct strbuf buf = STRBUF_INIT;
 193         if (!fp)
 194                 return -1;
 195         if (!no_graft_file_deprecated_advice &&
 196             advice_enabled(ADVICE_GRAFT_FILE_DEPRECATED))
 197                 advise(_("Support for <GIT_DIR>/info/grafts is deprecated\n"
 198                          "and will be removed in a future Git version.\n"
 199                          "\n"
 200                          "Please use \"git replace --convert-graft-file\"\n"
 201                          "to convert the grafts into replace refs.\n"
 202                          "\n"
 203                          "Turn this message off by running\n"
 204                          "\"git config advice.graftFileDeprecated false\""));
 205         while (!strbuf_getwholeline(&buf, fp, '\n')) {
 206                 /* The format is just "Commit Parent1 Parent2 ...\n" */
 207                 struct commit_graft *graft = read_graft_line(&buf);
 208                 if (!graft)
 209                         continue;
 210                 if (register_commit_graft(r, graft, 1))
 211                         error("duplicate graft data: %s", buf.buf);
 212         }
 213         fclose(fp);
 214         strbuf_release(&buf);
 215         return 0;
 216 }
 217
 218 void prepare_commit_graft(struct repository *r)
 219 {
 220         char *graft_file;
 221
 222         if (r->parsed_objects->commit_graft_prepared)
 223                 return;
 224         if (!startup_info->have_repository)
 225                 return;
 226
 227         graft_file = get_graft_file(r);
 228         read_graft_file(r, graft_file);
 229         /* make sure shallows are read */
 230         is_repository_shallow(r);
 231         r->parsed_objects->commit_graft_prepared = 1;
 232 }
 233
 234 struct commit_graft *lookup_commit_graft(struct repository *r, const struct object_id *oid)
 235 {
 236         int pos;
 237         prepare_commit_graft(r);
 238         pos = commit_graft_pos(r, oid);
 239         if (pos < 0)
 240                 return NULL;
 241         return r->parsed_objects->grafts[pos];
 242 }
 243
 244 int for_each_commit_graft(each_commit_graft_fn fn, void *cb_data)
 245 {
 246         int i, ret;
 247         for (i = ret = 0; i < the_repository->parsed_objects->grafts_nr && !ret; i++)
 248                 ret = fn(the_repository->parsed_objects->grafts[i], cb_data);
 249         return ret;
 250 }
 251
 252 struct commit_buffer {
 253         void *buffer;
 254         unsigned long size;
 255 };
 256 define_commit_slab(buffer_slab, struct commit_buffer);
 257
 258 struct buffer_slab *allocate_commit_buffer_slab(void)
 259 {
 260         struct buffer_slab *bs = xmalloc(sizeof(*bs));
 261         init_buffer_slab(bs);
 262         return bs;
 263 }
 264
 265 void free_commit_buffer_slab(struct buffer_slab *bs)
 266 {
 267         clear_buffer_slab(bs);
 268         free(bs);
 269 }
 270
 271 void set_commit_buffer(struct repository *r, struct commit *commit, void *buffer, unsigned long size)
 272 {
 273         struct commit_buffer *v = buffer_slab_at(
 274                 r->parsed_objects->buffer_slab, commit);
 275         v->buffer = buffer;
 276         v->size = size;
 277 }
 278
 279 const void *get_cached_commit_buffer(struct repository *r, const struct commit *commit, unsigned long *sizep)
 280 {
 281         struct commit_buffer *v = buffer_slab_peek(
 282                 r->parsed_objects->buffer_slab, commit);
 283         if (!v) {
 284                 if (sizep)
 285                         *sizep = 0;
 286                 return NULL;
 287         }
 288         if (sizep)
 289                 *sizep = v->size;
 290         return v->buffer;
 291 }
 292
 293 const void *repo_get_commit_buffer(struct repository *r,
 294                                    const struct commit *commit,
 295                                    unsigned long *sizep)
 296 {
 297         const void *ret = get_cached_commit_buffer(r, commit, sizep);
 298         if (!ret) {
 299                 enum object_type type;
 300                 unsigned long size;
 301                 ret = repo_read_object_file(r, &commit->object.oid, &type, &size);
 302                 if (!ret)
 303                         die("cannot read commit object %s",
 304                             oid_to_hex(&commit->object.oid));
 305                 if (type != OBJ_COMMIT)
 306                         die("expected commit for %s, got %s",
 307                             oid_to_hex(&commit->object.oid), type_name(type));
 308                 if (sizep)
 309                         *sizep = size;
 310         }
 311         return ret;
 312 }
 313
 314 void repo_unuse_commit_buffer(struct repository *r,
 315                               const struct commit *commit,
 316                               const void *buffer)
 317 {
 318         struct commit_buffer *v = buffer_slab_peek(
 319                 r->parsed_objects->buffer_slab, commit);
 320         if (!(v && v->buffer == buffer))
 321                 free((void *)buffer);
 322 }
 323
 324 void free_commit_buffer(struct parsed_object_pool *pool, struct commit *commit)
 325 {
 326         struct commit_buffer *v = buffer_slab_peek(
 327                 pool->buffer_slab, commit);
 328         if (v) {
 329                 FREE_AND_NULL(v->buffer);
 330                 v->size = 0;
 331         }
 332 }
 333
 334 static inline void set_commit_tree(struct commit *c, struct tree *t)
 335 {
 336         c->maybe_tree = t;
 337 }
 338
 339 struct tree *repo_get_commit_tree(struct repository *r,
 340                                   const struct commit *commit)
 341 {
 342         if (commit->maybe_tree || !commit->object.parsed)
 343                 return commit->maybe_tree;
 344
 345         if (commit_graph_position(commit) != COMMIT_NOT_FROM_GRAPH)
 346                 return get_commit_tree_in_graph(r, commit);
 347
 348         return NULL;
 349 }
 350
 351 struct object_id *get_commit_tree_oid(const struct commit *commit)
 352 {
 353         struct tree *tree = get_commit_tree(commit);
 354         return tree ? &tree->object.oid : NULL;
 355 }
 356
 357 void release_commit_memory(struct parsed_object_pool *pool, struct commit *c)
 358 {
 359         set_commit_tree(c, NULL);
 360         free_commit_buffer(pool, c);
 361         c->index = 0;
 362         free_commit_list(c->parents);
 363
 364         c->object.parsed = 0;
 365 }
 366
 367 const void *detach_commit_buffer(struct commit *commit, unsigned long *sizep)
 368 {
 369         struct commit_buffer *v = buffer_slab_peek(
 370                 the_repository->parsed_objects->buffer_slab, commit);
 371         void *ret;
 372
 373         if (!v) {
 374                 if (sizep)
 375                         *sizep = 0;
 376                 return NULL;
 377         }
 378         ret = v->buffer;
 379         if (sizep)
 380                 *sizep = v->size;
 381
 382         v->buffer = NULL;
 383         v->size = 0;
 384         return ret;
 385 }
 386
 387 int parse_commit_buffer(struct repository *r, struct commit *item, const void *buffer, unsigned long size, int check_graph)
 388 {
 389         const char *tail = buffer;
 390         const char *bufptr = buffer;
 391         struct object_id parent;
 392         struct commit_list **pptr;
 393         struct commit_graft *graft;
 394         const int tree_entry_len = the_hash_algo->hexsz + 5;
 395         const int parent_entry_len = the_hash_algo->hexsz + 7;
 396         struct tree *tree;
 397
 398         if (item->object.parsed)
 399                 return 0;
 400
 401         if (item->parents) {
 402                 /*
 403                  * Presumably this is leftover from an earlier failed parse;
 404                  * clear it out in preparation for us re-parsing (we'll hit the
 405                  * same error, but that's good, since it lets our caller know
 406                  * the result cannot be trusted.
 407                  */
 408                 free_commit_list(item->parents);
 409                 item->parents = NULL;
 410         }
 411
 412         tail += size;
 413         if (tail <= bufptr + tree_entry_len + 1 || memcmp(bufptr, "tree ", 5) ||
 414                         bufptr[tree_entry_len] != '\n')
 415                 return error("bogus commit object %s", oid_to_hex(&item->object.oid));
 416         if (get_oid_hex(bufptr + 5, &parent) < 0)
 417                 return error("bad tree pointer in commit %s",
 418                              oid_to_hex(&item->object.oid));
 419         tree = lookup_tree(r, &parent);
 420         if (!tree)
 421                 return error("bad tree pointer %s in commit %s",
 422                              oid_to_hex(&parent),
 423                              oid_to_hex(&item->object.oid));
 424         set_commit_tree(item, tree);
 425         bufptr += tree_entry_len + 1; /* "tree " + "hex sha1" + "\n" */
 426         pptr = &item->parents;
 427
 428         graft = lookup_commit_graft(r, &item->object.oid);
 429         if (graft)
 430                 r->parsed_objects->substituted_parent = 1;
 431         while (bufptr + parent_entry_len < tail && !memcmp(bufptr, "parent ", 7)) {
 432                 struct commit *new_parent;
 433
 434                 if (tail <= bufptr + parent_entry_len + 1 ||
 435                     get_oid_hex(bufptr + 7, &parent) ||
 436                     bufptr[parent_entry_len] != '\n')
 437                         return error("bad parents in commit %s", oid_to_hex(&item->object.oid));
 438                 bufptr += parent_entry_len + 1;
 439                 /*
 440                  * The clone is shallow if nr_parent < 0, and we must
 441                  * not traverse its real parents even when we unhide them.
 442                  */
 443                 if (graft && (graft->nr_parent < 0 || grafts_replace_parents))
 444                         continue;
 445                 new_parent = lookup_commit(r, &parent);
 446                 if (!new_parent)
 447                         return error("bad parent %s in commit %s",
 448                                      oid_to_hex(&parent),
 449                                      oid_to_hex(&item->object.oid));
 450                 pptr = &commit_list_insert(new_parent, pptr)->next;
 451         }
 452         if (graft) {
 453                 int i;
 454                 struct commit *new_parent;
 455                 for (i = 0; i < graft->nr_parent; i++) {
 456                         new_parent = lookup_commit(r,
 457                                                    &graft->parent[i]);
 458                         if (!new_parent)
 459                                 return error("bad graft parent %s in commit %s",
 460                                              oid_to_hex(&graft->parent[i]),
 461                                              oid_to_hex(&item->object.oid));
 462                         pptr = &commit_list_insert(new_parent, pptr)->next;
 463                 }
 464         }
 465         item->date = parse_commit_date(bufptr, tail);
 466
 467         if (check_graph)
 468                 load_commit_graph_info(r, item);
 469
 470         item->object.parsed = 1;
 471         return 0;
 472 }
 473
 474 int repo_parse_commit_internal(struct repository *r,
 475                                struct commit *item,
 476                                int quiet_on_missing,
 477                                int use_commit_graph)
 478 {
 479         enum object_type type;
 480         void *buffer;
 481         unsigned long size;
 482         int ret;
 483
 484         if (!item)
 485                 return -1;
 486         if (item->object.parsed)
 487                 return 0;
 488         if (use_commit_graph && parse_commit_in_graph(r, item))
 489                 return 0;
 490         buffer = repo_read_object_file(r, &item->object.oid, &type, &size);
 491         if (!buffer)
 492                 return quiet_on_missing ? -1 :
 493                         error("Could not read %s",
 494                              oid_to_hex(&item->object.oid));
 495         if (type != OBJ_COMMIT) {
 496                 free(buffer);
 497                 return error("Object %s not a commit",
 498                              oid_to_hex(&item->object.oid));
 499         }
 500
 501         ret = parse_commit_buffer(r, item, buffer, size, 0);
 502         if (save_commit_buffer && !ret) {
 503                 set_commit_buffer(r, item, buffer, size);
 504                 return 0;
 505         }
 506         free(buffer);
 507         return ret;
 508 }
 509
 510 int repo_parse_commit_gently(struct repository *r,
 511                              struct commit *item, int quiet_on_missing)
 512 {
 513         return repo_parse_commit_internal(r, item, quiet_on_missing, 1);
 514 }
 515
 516 void parse_commit_or_die(struct commit *item)
 517 {
 518         if (parse_commit(item))
 519                 die("unable to parse commit %s",
 520                     item ? oid_to_hex(&item->object.oid) : "(null)");
 521 }
 522
 523 int find_commit_subject(const char *commit_buffer, const char **subject)
 524 {
 525         const char *eol;
 526         const char *p = commit_buffer;
 527
 528         while (*p && (*p != '\n' || p[1] != '\n'))
 529                 p++;
 530         if (*p) {
 531                 p = skip_blank_lines(p + 2);
 532                 eol = strchrnul(p, '\n');
 533         } else
 534                 eol = p;
 535
 536         *subject = p;
 537
 538         return eol - p;
 539 }
 540
 541 size_t commit_subject_length(const char *body)
 542 {
 543         const char *p = body;
 544         while (*p) {
 545                 const char *next = skip_blank_lines(p);
 546                 if (next != p)
 547                         break;
 548                 p = strchrnul(p, '\n');
 549                 if (*p)
 550                         p++;
 551         }
 552         return p - body;
 553 }
 554
 555 struct commit_list *commit_list_insert(struct commit *item, struct commit_list **list_p)
 556 {
 557         struct commit_list *new_list = xmalloc(sizeof(struct commit_list));
 558         new_list->item = item;
 559         new_list->next = *list_p;
 560         *list_p = new_list;
 561         return new_list;
 562 }
 563
 564 int commit_list_contains(struct commit *item, struct commit_list *list)
 565 {
 566         while (list) {
 567                 if (list->item == item)
 568                         return 1;
 569                 list = list->next;
 570         }
 571
 572         return 0;
 573 }
 574
 575 unsigned commit_list_count(const struct commit_list *l)
 576 {
 577         unsigned c = 0;
 578         for (; l; l = l->next )
 579                 c++;
 580         return c;
 581 }
 582
 583 struct commit_list *copy_commit_list(struct commit_list *list)
 584 {
 585         struct commit_list *head = NULL;
 586         struct commit_list **pp = &head;
 587         while (list) {
 588                 pp = commit_list_append(list->item, pp);
 589                 list = list->next;
 590         }
 591         return head;
 592 }
 593
 594 struct commit_list *reverse_commit_list(struct commit_list *list)
 595 {
 596         struct commit_list *next = NULL, *current, *backup;
 597         for (current = list; current; current = backup) {
 598                 backup = current->next;
 599                 current->next = next;
 600                 next = current;
 601         }
 602         return next;
 603 }
 604
 605 void free_commit_list(struct commit_list *list)
 606 {
 607         while (list)
 608                 pop_commit(&list);
 609 }
 610
 611 struct commit_list * commit_list_insert_by_date(struct commit *item, struct commit_list **list)
 612 {
 613         struct commit_list **pp = list;
 614         struct commit_list *p;
 615         while ((p = *pp) != NULL) {
 616                 if (p->item->date < item->date) {
 617                         break;
 618                 }
 619                 pp = &p->next;
 620         }
 621         return commit_list_insert(item, pp);
 622 }
 623
 624 static int commit_list_compare_by_date(const void *a, const void *b)
 625 {
 626         timestamp_t a_date = ((const struct commit_list *)a)->item->date;
 627         timestamp_t b_date = ((const struct commit_list *)b)->item->date;
 628         if (a_date < b_date)
 629                 return 1;
 630         if (a_date > b_date)
 631                 return -1;
 632         return 0;
 633 }
 634
 635 static void *commit_list_get_next(const void *a)
 636 {
 637         return ((const struct commit_list *)a)->next;
 638 }
 639
 640 static void commit_list_set_next(void *a, void *next)
 641 {
 642         ((struct commit_list *)a)->next = next;
 643 }
 644
 645 void commit_list_sort_by_date(struct commit_list **list)
 646 {
 647         *list = llist_mergesort(*list, commit_list_get_next, commit_list_set_next,
 648                                 commit_list_compare_by_date);
 649 }
 650
 651 struct commit *pop_most_recent_commit(struct commit_list **list,
 652                                       unsigned int mark)
 653 {
 654         struct commit *ret = pop_commit(list);
 655         struct commit_list *parents = ret->parents;
 656
 657         while (parents) {
 658                 struct commit *commit = parents->item;
 659                 if (!parse_commit(commit) && !(commit->object.flags & mark)) {
 660                         commit->object.flags |= mark;
 661                         commit_list_insert_by_date(commit, list);
 662                 }
 663                 parents = parents->next;
 664         }
 665         return ret;
 666 }
 667
 668 static void clear_commit_marks_1(struct commit_list **plist,
 669                                  struct commit *commit, unsigned int mark)
 670 {
 671         while (commit) {
 672                 struct commit_list *parents;
 673
 674                 if (!(mark & commit->object.flags))
 675                         return;
 676
 677                 commit->object.flags &= ~mark;
 678
 679                 parents = commit->parents;
 680                 if (!parents)
 681                         return;
 682
 683                 while ((parents = parents->next))
 684                         commit_list_insert(parents->item, plist);
 685
 686                 commit = commit->parents->item;
 687         }
 688 }
 689
 690 void clear_commit_marks_many(int nr, struct commit **commit, unsigned int mark)
 691 {
 692         struct commit_list *list = NULL;
 693
 694         while (nr--) {
 695                 clear_commit_marks_1(&list, *commit, mark);
 696                 commit++;
 697         }
 698         while (list)
 699                 clear_commit_marks_1(&list, pop_commit(&list), mark);
 700 }
 701
 702 void clear_commit_marks(struct commit *commit, unsigned int mark)
 703 {
 704         clear_commit_marks_many(1, &commit, mark);
 705 }
 706
 707 struct commit *pop_commit(struct commit_list **stack)
 708 {
 709         struct commit_list *top = *stack;
 710         struct commit *item = top ? top->item : NULL;
 711
 712         if (top) {
 713                 *stack = top->next;
 714                 free(top);
 715         }
 716         return item;
 717 }
 718
 719 /*
 720  * Topological sort support
 721  */
 722
 723 /* count number of children that have not been emitted */
 724 define_commit_slab(indegree_slab, int);
 725
 726 define_commit_slab(author_date_slab, timestamp_t);
 727
 728 void record_author_date(struct author_date_slab *author_date,
 729                         struct commit *commit)
 730 {
 731         const char *buffer = get_commit_buffer(commit, NULL);
 732         struct ident_split ident;
 733         const char *ident_line;
 734         size_t ident_len;
 735         char *date_end;
 736         timestamp_t date;
 737
 738         ident_line = find_commit_header(buffer, "author", &ident_len);
 739         if (!ident_line)
 740                 goto fail_exit; /* no author line */
 741         if (split_ident_line(&ident, ident_line, ident_len) ||
 742             !ident.date_begin || !ident.date_end)
 743                 goto fail_exit; /* malformed "author" line */
 744
 745         date = parse_timestamp(ident.date_begin, &date_end, 10);
 746         if (date_end != ident.date_end)
 747                 goto fail_exit; /* malformed date */
 748         *(author_date_slab_at(author_date, commit)) = date;
 749
 750 fail_exit:
 751         unuse_commit_buffer(commit, buffer);
 752 }
 753
 754 int compare_commits_by_author_date(const void *a_, const void *b_,
 755                                    void *cb_data)
 756 {
 757         const struct commit *a = a_, *b = b_;
 758         struct author_date_slab *author_date = cb_data;
 759         timestamp_t a_date = *(author_date_slab_at(author_date, a));
 760         timestamp_t b_date = *(author_date_slab_at(author_date, b));
 761
 762         /* newer commits with larger date first */
 763         if (a_date < b_date)
 764                 return 1;
 765         else if (a_date > b_date)
 766                 return -1;
 767         return 0;
 768 }
 769
 770 int compare_commits_by_gen_then_commit_date(const void *a_, const void *b_, void *unused)
 771 {
 772         const struct commit *a = a_, *b = b_;
 773         const timestamp_t generation_a = commit_graph_generation(a),
 774                           generation_b = commit_graph_generation(b);
 775
 776         /* newer commits first */
 777         if (generation_a < generation_b)
 778                 return 1;
 779         else if (generation_a > generation_b)
 780                 return -1;
 781
 782         /* use date as a heuristic when generations are equal */
 783         if (a->date < b->date)
 784                 return 1;
 785         else if (a->date > b->date)
 786                 return -1;
 787         return 0;
 788 }
 789
 790 int compare_commits_by_commit_date(const void *a_, const void *b_, void *unused)
 791 {
 792         const struct commit *a = a_, *b = b_;
 793         /* newer commits with larger date first */
 794         if (a->date < b->date)
 795                 return 1;
 796         else if (a->date > b->date)
 797                 return -1;
 798         return 0;
 799 }
 800
 801 /*
 802  * Performs an in-place topological sort on the list supplied.
 803  */
 804 void sort_in_topological_order(struct commit_list **list, enum rev_sort_order sort_order)
 805 {
 806         struct commit_list *next, *orig = *list;
 807         struct commit_list **pptr;
 808         struct indegree_slab indegree;
 809         struct prio_queue queue;
 810         struct commit *commit;
 811         struct author_date_slab author_date;
 812
 813         if (!orig)
 814                 return;
 815         *list = NULL;
 816
 817         init_indegree_slab(&indegree);
 818         memset(&queue, '\0', sizeof(queue));
 819
 820         switch (sort_order) {
 821         default: /* REV_SORT_IN_GRAPH_ORDER */
 822                 queue.compare = NULL;
 823                 break;
 824         case REV_SORT_BY_COMMIT_DATE:
 825                 queue.compare = compare_commits_by_commit_date;
 826                 break;
 827         case REV_SORT_BY_AUTHOR_DATE:
 828                 init_author_date_slab(&author_date);
 829                 queue.compare = compare_commits_by_author_date;
 830                 queue.cb_data = &author_date;
 831                 break;
 832         }
 833
 834         /* Mark them and clear the indegree */
 835         for (next = orig; next; next = next->next) {
 836                 struct commit *commit = next->item;
 837                 *(indegree_slab_at(&indegree, commit)) = 1;
 838                 /* also record the author dates, if needed */
 839                 if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 840                         record_author_date(&author_date, commit);
 841         }
 842
 843         /* update the indegree */
 844         for (next = orig; next; next = next->next) {
 845                 struct commit_list *parents = next->item->parents;
 846                 while (parents) {
 847                         struct commit *parent = parents->item;
 848                         int *pi = indegree_slab_at(&indegree, parent);
 849
 850                         if (*pi)
 851                                 (*pi)++;
 852                         parents = parents->next;
 853                 }
 854         }
 855
 856         /*
 857          * find the tips
 858          *
 859          * tips are nodes not reachable from any other node in the list
 860          *
 861          * the tips serve as a starting set for the work queue.
 862          */
 863         for (next = orig; next; next = next->next) {
 864                 struct commit *commit = next->item;
 865
 866                 if (*(indegree_slab_at(&indegree, commit)) == 1)
 867                         prio_queue_put(&queue, commit);
 868         }
 869
 870         /*
 871          * This is unfortunate; the initial tips need to be shown
 872          * in the order given from the revision traversal machinery.
 873          */
 874         if (sort_order == REV_SORT_IN_GRAPH_ORDER)
 875                 prio_queue_reverse(&queue);
 876
 877         /* We no longer need the commit list */
 878         free_commit_list(orig);
 879
 880         pptr = list;
 881         *list = NULL;
 882         while ((commit = prio_queue_get(&queue)) != NULL) {
 883                 struct commit_list *parents;
 884
 885                 for (parents = commit->parents; parents ; parents = parents->next) {
 886                         struct commit *parent = parents->item;
 887                         int *pi = indegree_slab_at(&indegree, parent);
 888
 889                         if (!*pi)
 890                                 continue;
 891
 892                         /*
 893                          * parents are only enqueued for emission
 894                          * when all their children have been emitted thereby
 895                          * guaranteeing topological order.
 896                          */
 897                         if (--(*pi) == 1)
 898                                 prio_queue_put(&queue, parent);
 899                 }
 900                 /*
 901                  * all children of commit have already been
 902                  * emitted. we can emit it now.
 903                  */
 904                 *(indegree_slab_at(&indegree, commit)) = 0;
 905
 906                 pptr = &commit_list_insert(commit, pptr)->next;
 907         }
 908
 909         clear_indegree_slab(&indegree);
 910         clear_prio_queue(&queue);
 911         if (sort_order == REV_SORT_BY_AUTHOR_DATE)
 912                 clear_author_date_slab(&author_date);
 913 }
 914
 915 struct rev_collect {
 916         struct commit **commit;
 917         int nr;
 918         int alloc;
 919         unsigned int initial : 1;
 920 };
 921
 922 static void add_one_commit(struct object_id *oid, struct rev_collect *revs)
 923 {
 924         struct commit *commit;
 925
 926         if (is_null_oid(oid))
 927                 return;
 928
 929         commit = lookup_commit(the_repository, oid);
 930         if (!commit ||
 931             (commit->object.flags & TMP_MARK) ||
 932             parse_commit(commit))
 933                 return;
 934
 935         ALLOC_GROW(revs->commit, revs->nr + 1, revs->alloc);
 936         revs->commit[revs->nr++] = commit;
 937         commit->object.flags |= TMP_MARK;
 938 }
 939
 940 static int collect_one_reflog_ent(struct object_id *ooid, struct object_id *noid,
 941                                   const char *ident, timestamp_t timestamp,
 942                                   int tz, const char *message, void *cbdata)
 943 {
 944         struct rev_collect *revs = cbdata;
 945
 946         if (revs->initial) {
 947                 revs->initial = 0;
 948                 add_one_commit(ooid, revs);
 949         }
 950         add_one_commit(noid, revs);
 951         return 0;
 952 }
 953
 954 struct commit *get_fork_point(const char *refname, struct commit *commit)
 955 {
 956         struct object_id oid;
 957         struct rev_collect revs;
 958         struct commit_list *bases;
 959         int i;
 960         struct commit *ret = NULL;
 961         char *full_refname;
 962
 963         switch (dwim_ref(refname, strlen(refname), &oid, &full_refname, 0)) {
 964         case 0:
 965                 die("No such ref: '%s'", refname);
 966         case 1:
 967                 break; /* good */
 968         default:
 969                 die("Ambiguous refname: '%s'", refname);
 970         }
 971
 972         memset(&revs, 0, sizeof(revs));
 973         revs.initial = 1;
 974         for_each_reflog_ent(full_refname, collect_one_reflog_ent, &revs);
 975
 976         if (!revs.nr)
 977                 add_one_commit(&oid, &revs);
 978
 979         for (i = 0; i < revs.nr; i++)
 980                 revs.commit[i]->object.flags &= ~TMP_MARK;
 981
 982         bases = get_merge_bases_many(commit, revs.nr, revs.commit);
 983
 984         /*
 985          * There should be one and only one merge base, when we found
 986          * a common ancestor among reflog entries.
 987          */
 988         if (!bases || bases->next)
 989                 goto cleanup_return;
 990
 991         /* And the found one must be one of the reflog entries */
 992         for (i = 0; i < revs.nr; i++)
 993                 if (&bases->item->object == &revs.commit[i]->object)
 994                         break; /* found */
 995         if (revs.nr <= i)
 996                 goto cleanup_return;
 997
 998         ret = bases->item;
 999
1000 cleanup_return:
1001         free_commit_list(bases);
1002         free(full_refname);
1003         return ret;
1004 }
1005
1006 /*
1007  * Indexed by hash algorithm identifier.
1008  */
1009 static const char *gpg_sig_headers[] = {
1010         NULL,
1011         "gpgsig",
1012         "gpgsig-sha256",
1013 };
1014
1015 int sign_with_header(struct strbuf *buf, const char *keyid)
1016 {
1017         struct strbuf sig = STRBUF_INIT;
1018         int inspos, copypos;
1019         const char *eoh;
1020         const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(the_hash_algo)];
1021         int gpg_sig_header_len = strlen(gpg_sig_header);
1022
1023         /* find the end of the header */
1024         eoh = strstr(buf->buf, "\n\n");
1025         if (!eoh)
1026                 inspos = buf->len;
1027         else
1028                 inspos = eoh - buf->buf + 1;
1029
1030         if (!keyid || !*keyid)
1031                 keyid = get_signing_key();
1032         if (sign_buffer(buf, &sig, keyid)) {
1033                 strbuf_release(&sig);
1034                 return -1;
1035         }
1036
1037         for (copypos = 0; sig.buf[copypos]; ) {
1038                 const char *bol = sig.buf + copypos;
1039                 const char *eol = strchrnul(bol, '\n');
1040                 int len = (eol - bol) + !!*eol;
1041
1042                 if (!copypos) {
1043                         strbuf_insert(buf, inspos, gpg_sig_header, gpg_sig_header_len);
1044                         inspos += gpg_sig_header_len;
1045                 }
1046                 strbuf_insertstr(buf, inspos++, " ");
1047                 strbuf_insert(buf, inspos, bol, len);
1048                 inspos += len;
1049                 copypos += len;
1050         }
1051         strbuf_release(&sig);
1052         return 0;
1053 }
1054
1055
1056
1057 int parse_signed_commit(const struct commit *commit,
1058                         struct strbuf *payload, struct strbuf *signature,
1059                         const struct git_hash_algo *algop)
1060 {
1061         unsigned long size;
1062         const char *buffer = get_commit_buffer(commit, &size);
1063         int ret = parse_buffer_signed_by_header(buffer, size, payload, signature, algop);
1064
1065         unuse_commit_buffer(commit, buffer);
1066         return ret;
1067 }
1068
1069 int parse_buffer_signed_by_header(const char *buffer,
1070                                   unsigned long size,
1071                                   struct strbuf *payload,
1072                                   struct strbuf *signature,
1073                                   const struct git_hash_algo *algop)
1074 {
1075         int in_signature = 0, saw_signature = 0, other_signature = 0;
1076         const char *line, *tail, *p;
1077         const char *gpg_sig_header = gpg_sig_headers[hash_algo_by_ptr(algop)];
1078
1079         line = buffer;
1080         tail = buffer + size;
1081         while (line < tail) {
1082                 const char *sig = NULL;
1083                 const char *next = memchr(line, '\n', tail - line);
1084
1085                 next = next ? next + 1 : tail;
1086                 if (in_signature && line[0] == ' ')
1087                         sig = line + 1;
1088                 else if (skip_prefix(line, gpg_sig_header, &p) &&
1089                          *p == ' ') {
1090                         sig = line + strlen(gpg_sig_header) + 1;
1091                         other_signature = 0;
1092                 }
1093                 else if (starts_with(line, "gpgsig"))
1094                         other_signature = 1;
1095                 else if (other_signature && line[0] != ' ')
1096                         other_signature = 0;
1097                 if (sig) {
1098                         strbuf_add(signature, sig, next - sig);
1099                         saw_signature = 1;
1100                         in_signature = 1;
1101                 } else {
1102                         if (*line == '\n')
1103                                 /* dump the whole remainder of the buffer */
1104                                 next = tail;
1105                         if (!other_signature)
1106                                 strbuf_add(payload, line, next - line);
1107                         in_signature = 0;
1108                 }
1109                 line = next;
1110         }
1111         return saw_signature;
1112 }
1113
1114 int remove_signature(struct strbuf *buf)
1115 {
1116         const char *line = buf->buf;
1117         const char *tail = buf->buf + buf->len;
1118         int in_signature = 0;
1119         struct sigbuf {
1120                 const char *start;
1121                 const char *end;
1122         } sigs[2], *sigp = &sigs[0];
1123         int i;
1124         const char *orig_buf = buf->buf;
1125
1126         memset(sigs, 0, sizeof(sigs));
1127
1128         while (line < tail) {
1129                 const char *next = memchr(line, '\n', tail - line);
1130                 next = next ? next + 1 : tail;
1131
1132                 if (in_signature && line[0] == ' ')
1133                         sigp->end = next;
1134                 else if (starts_with(line, "gpgsig")) {
1135                         int i;
1136                         for (i = 1; i < GIT_HASH_NALGOS; i++) {
1137                                 const char *p;
1138                                 if (skip_prefix(line, gpg_sig_headers[i], &p) &&
1139                                     *p == ' ') {
1140                                         sigp->start = line;
1141                                         sigp->end = next;
1142                                         in_signature = 1;
1143                                 }
1144                         }
1145                 } else {
1146                         if (*line == '\n')
1147                                 /* dump the whole remainder of the buffer */
1148                                 next = tail;
1149                         if (in_signature && sigp - sigs != ARRAY_SIZE(sigs))
1150                                 sigp++;
1151                         in_signature = 0;
1152                 }
1153                 line = next;
1154         }
1155
1156         for (i = ARRAY_SIZE(sigs) - 1; i >= 0; i--)
1157                 if (sigs[i].start)
1158                         strbuf_remove(buf, sigs[i].start - orig_buf, sigs[i].end - sigs[i].start);
1159
1160         return sigs[0].start != NULL;
1161 }
1162
1163 static void handle_signed_tag(struct commit *parent, struct commit_extra_header ***tail)
1164 {
1165         struct merge_remote_desc *desc;
1166         struct commit_extra_header *mergetag;
1167         char *buf;
1168         unsigned long size;
1169         enum object_type type;
1170         struct strbuf payload = STRBUF_INIT;
1171         struct strbuf signature = STRBUF_INIT;
1172
1173         desc = merge_remote_util(parent);
1174         if (!desc || !desc->obj)
1175                 return;
1176         buf = read_object_file(&desc->obj->oid, &type, &size);
1177         if (!buf || type != OBJ_TAG)
1178                 goto free_return;
1179         if (!parse_signature(buf, size, &payload, &signature))
1180                 goto free_return;
1181         /*
1182          * We could verify this signature and either omit the tag when
1183          * it does not validate, but the integrator may not have the
1184          * public key of the signer of the tag being merged, while a
1185          * later auditor may have it while auditing, so let's not run
1186          * verify-signed-buffer here for now...
1187          *
1188          * if (verify_signed_buffer(buf, len, buf + len, size - len, ...))
1189          *      warn("warning: signed tag unverified.");
1190          */
1191         CALLOC_ARRAY(mergetag, 1);
1192         mergetag->key = xstrdup("mergetag");
1193         mergetag->value = buf;
1194         mergetag->len = size;
1195
1196         **tail = mergetag;
1197         *tail = &mergetag->next;
1198         strbuf_release(&payload);
1199         strbuf_release(&signature);
1200         return;
1201
1202 free_return:
1203         free(buf);
1204 }
1205
1206 int check_commit_signature(const struct commit *commit, struct signature_check *sigc)
1207 {
1208         struct strbuf payload = STRBUF_INIT;
1209         struct strbuf signature = STRBUF_INIT;
1210         int ret = 1;
1211
1212         sigc->result = 'N';
1213
1214         if (parse_signed_commit(commit, &payload, &signature, the_hash_algo) <= 0)
1215                 goto out;
1216
1217         sigc->payload_type = SIGNATURE_PAYLOAD_COMMIT;
1218         sigc->payload = strbuf_detach(&payload, &sigc->payload_len);
1219         ret = check_signature(sigc, signature.buf, signature.len);
1220
1221  out:
1222         strbuf_release(&payload);
1223         strbuf_release(&signature);
1224
1225         return ret;
1226 }
1227
1228 void verify_merge_signature(struct commit *commit, int verbosity,
1229                             int check_trust)
1230 {
1231         char hex[GIT_MAX_HEXSZ + 1];
1232         struct signature_check signature_check;
1233         int ret;
1234         memset(&signature_check, 0, sizeof(signature_check));
1235
1236         ret = check_commit_signature(commit, &signature_check);
1237
1238         find_unique_abbrev_r(hex, &commit->object.oid, DEFAULT_ABBREV);
1239         switch (signature_check.result) {
1240         case 'G':
1241                 if (ret || (check_trust && signature_check.trust_level < TRUST_MARGINAL))
1242                         die(_("Commit %s has an untrusted GPG signature, "
1243                               "allegedly by %s."), hex, signature_check.signer);
1244                 break;
1245         case 'B':
1246                 die(_("Commit %s has a bad GPG signature "
1247                       "allegedly by %s."), hex, signature_check.signer);
1248         default: /* 'N' */
1249                 die(_("Commit %s does not have a GPG signature."), hex);
1250         }
1251         if (verbosity >= 0 && signature_check.result == 'G')
1252                 printf(_("Commit %s has a good GPG signature by %s\n"),
1253                        hex, signature_check.signer);
1254
1255         signature_check_clear(&signature_check);
1256 }
1257
1258 void append_merge_tag_headers(struct commit_list *parents,
1259                               struct commit_extra_header ***tail)
1260 {
1261         while (parents) {
1262                 struct commit *parent = parents->item;
1263                 handle_signed_tag(parent, tail);
1264                 parents = parents->next;
1265         }
1266 }
1267
1268 static void add_extra_header(struct strbuf *buffer,
1269                              struct commit_extra_header *extra)
1270 {
1271         strbuf_addstr(buffer, extra->key);
1272         if (extra->len)
1273                 strbuf_add_lines(buffer, " ", extra->value, extra->len);
1274         else
1275                 strbuf_addch(buffer, '\n');
1276 }
1277
1278 struct commit_extra_header *read_commit_extra_headers(struct commit *commit,
1279                                                       const char **exclude)
1280 {
1281         struct commit_extra_header *extra = NULL;
1282         unsigned long size;
1283         const char *buffer = get_commit_buffer(commit, &size);
1284         extra = read_commit_extra_header_lines(buffer, size, exclude);
1285         unuse_commit_buffer(commit, buffer);
1286         return extra;
1287 }
1288
1289 int for_each_mergetag(each_mergetag_fn fn, struct commit *commit, void *data)
1290 {
1291         struct commit_extra_header *extra, *to_free;
1292         int res = 0;
1293
1294         to_free = read_commit_extra_headers(commit, NULL);
1295         for (extra = to_free; !res && extra; extra = extra->next) {
1296                 if (strcmp(extra->key, "mergetag"))
1297                         continue; /* not a merge tag */
1298                 res = fn(commit, extra, data);
1299         }
1300         free_commit_extra_headers(to_free);
1301         return res;
1302 }
1303
1304 static inline int standard_header_field(const char *field, size_t len)
1305 {
1306         return ((len == 4 && !memcmp(field, "tree", 4)) ||
1307                 (len == 6 && !memcmp(field, "parent", 6)) ||
1308                 (len == 6 && !memcmp(field, "author", 6)) ||
1309                 (len == 9 && !memcmp(field, "committer", 9)) ||
1310                 (len == 8 && !memcmp(field, "encoding", 8)));
1311 }
1312
1313 static int excluded_header_field(const char *field, size_t len, const char **exclude)
1314 {
1315         if (!exclude)
1316                 return 0;
1317
1318         while (*exclude) {
1319                 size_t xlen = strlen(*exclude);
1320                 if (len == xlen && !memcmp(field, *exclude, xlen))
1321                         return 1;
1322                 exclude++;
1323         }
1324         return 0;
1325 }
1326
1327 static struct commit_extra_header *read_commit_extra_header_lines(
1328         const char *buffer, size_t size,
1329         const char **exclude)
1330 {
1331         struct commit_extra_header *extra = NULL, **tail = &extra, *it = NULL;
1332         const char *line, *next, *eof, *eob;
1333         struct strbuf buf = STRBUF_INIT;
1334
1335         for (line = buffer, eob = line + size;
1336              line < eob && *line != '\n';
1337              line = next) {
1338                 next = memchr(line, '\n', eob - line);
1339                 next = next ? next + 1 : eob;
1340                 if (*line == ' ') {
1341                         /* continuation */
1342                         if (it)
1343                                 strbuf_add(&buf, line + 1, next - (line + 1));
1344                         continue;
1345                 }
1346                 if (it)
1347                         it->value = strbuf_detach(&buf, &it->len);
1348                 strbuf_reset(&buf);
1349                 it = NULL;
1350
1351                 eof = memchr(line, ' ', next - line);
1352                 if (!eof)
1353                         eof = next;
1354                 else if (standard_header_field(line, eof - line) ||
1355                          excluded_header_field(line, eof - line, exclude))
1356                         continue;
1357
1358                 CALLOC_ARRAY(it, 1);
1359                 it->key = xmemdupz(line, eof-line);
1360                 *tail = it;
1361                 tail = &it->next;
1362                 if (eof + 1 < next)
1363                         strbuf_add(&buf, eof + 1, next - (eof + 1));
1364         }
1365         if (it)
1366                 it->value = strbuf_detach(&buf, &it->len);
1367         return extra;
1368 }
1369
1370 void free_commit_extra_headers(struct commit_extra_header *extra)
1371 {
1372         while (extra) {
1373                 struct commit_extra_header *next = extra->next;
1374                 free(extra->key);
1375                 free(extra->value);
1376                 free(extra);
1377                 extra = next;
1378         }
1379 }
1380
1381 int commit_tree(const char *msg, size_t msg_len, const struct object_id *tree,
1382                 struct commit_list *parents, struct object_id *ret,
1383                 const char *author, const char *sign_commit)
1384 {
1385         struct commit_extra_header *extra = NULL, **tail = &extra;
1386         int result;
1387
1388         append_merge_tag_headers(parents, &tail);
1389         result = commit_tree_extended(msg, msg_len, tree, parents, ret, author,
1390                                       NULL, sign_commit, extra);
1391         free_commit_extra_headers(extra);
1392         return result;
1393 }
1394
1395 static int find_invalid_utf8(const char *buf, int len)
1396 {
1397         int offset = 0;
1398         static const unsigned int max_codepoint[] = {
1399                 0x7f, 0x7ff, 0xffff, 0x10ffff
1400         };
1401
1402         while (len) {
1403                 unsigned char c = *buf++;
1404                 int bytes, bad_offset;
1405                 unsigned int codepoint;
1406                 unsigned int min_val, max_val;
1407
1408                 len--;
1409                 offset++;
1410
1411                 /* Simple US-ASCII? No worries. */
1412                 if (c < 0x80)
1413                         continue;
1414
1415                 bad_offset = offset-1;
1416
1417                 /*
1418                  * Count how many more high bits set: that's how
1419                  * many more bytes this sequence should have.
1420                  */
1421                 bytes = 0;
1422                 while (c & 0x40) {
1423                         c <<= 1;
1424                         bytes++;
1425                 }
1426
1427                 /*
1428                  * Must be between 1 and 3 more bytes.  Longer sequences result in
1429                  * codepoints beyond U+10FFFF, which are guaranteed never to exist.
1430                  */
1431                 if (bytes < 1 || 3 < bytes)
1432                         return bad_offset;
1433
1434                 /* Do we *have* that many bytes? */
1435                 if (len < bytes)
1436                         return bad_offset;
1437
1438                 /*
1439                  * Place the encoded bits at the bottom of the value and compute the
1440                  * valid range.
1441                  */
1442                 codepoint = (c & 0x7f) >> bytes;
1443                 min_val = max_codepoint[bytes-1] + 1;
1444                 max_val = max_codepoint[bytes];
1445
1446                 offset += bytes;
1447                 len -= bytes;
1448
1449                 /* And verify that they are good continuation bytes */
1450                 do {
1451                         codepoint <<= 6;
1452                         codepoint |= *buf & 0x3f;
1453                         if ((*buf++ & 0xc0) != 0x80)
1454                                 return bad_offset;
1455                 } while (--bytes);
1456
1457                 /* Reject codepoints that are out of range for the sequence length. */
1458                 if (codepoint < min_val || codepoint > max_val)
1459                         return bad_offset;
1460                 /* Surrogates are only for UTF-16 and cannot be encoded in UTF-8. */
1461                 if ((codepoint & 0x1ff800) == 0xd800)
1462                         return bad_offset;
1463                 /* U+xxFFFE and U+xxFFFF are guaranteed non-characters. */
1464                 if ((codepoint & 0xfffe) == 0xfffe)
1465                         return bad_offset;
1466                 /* So are anything in the range U+FDD0..U+FDEF. */
1467                 if (codepoint >= 0xfdd0 && codepoint <= 0xfdef)
1468                         return bad_offset;
1469         }
1470         return -1;
1471 }
1472
1473 /*
1474  * This verifies that the buffer is in proper utf8 format.
1475  *
1476  * If it isn't, it assumes any non-utf8 characters are Latin1,
1477  * and does the conversion.
1478  */
1479 static int verify_utf8(struct strbuf *buf)
1480 {
1481         int ok = 1;
1482         long pos = 0;
1483
1484         for (;;) {
1485                 int bad;
1486                 unsigned char c;
1487                 unsigned char replace[2];
1488
1489                 bad = find_invalid_utf8(buf->buf + pos, buf->len - pos);
1490                 if (bad < 0)
1491                         return ok;
1492                 pos += bad;
1493                 ok = 0;
1494                 c = buf->buf[pos];
1495                 strbuf_remove(buf, pos, 1);
1496
1497                 /* We know 'c' must be in the range 128-255 */
1498                 replace[0] = 0xc0 + (c >> 6);
1499                 replace[1] = 0x80 + (c & 0x3f);
1500                 strbuf_insert(buf, pos, replace, 2);
1501                 pos += 2;
1502         }
1503 }
1504
1505 static const char commit_utf8_warn[] =
1506 N_("Warning: commit message did not conform to UTF-8.\n"
1507    "You may want to amend it after fixing the message, or set the config\n"
1508    "variable i18n.commitencoding to the encoding your project uses.\n");
1509
1510 int commit_tree_extended(const char *msg, size_t msg_len,
1511                          const struct object_id *tree,
1512                          struct commit_list *parents, struct object_id *ret,
1513                          const char *author, const char *committer,
1514                          const char *sign_commit,
1515                          struct commit_extra_header *extra)
1516 {
1517         int result;
1518         int encoding_is_utf8;
1519         struct strbuf buffer;
1520
1521         assert_oid_type(tree, OBJ_TREE);
1522
1523         if (memchr(msg, '\0', msg_len))
1524                 return error("a NUL byte in commit log message not allowed.");
1525
1526         /* Not having i18n.commitencoding is the same as having utf-8 */
1527         encoding_is_utf8 = is_encoding_utf8(git_commit_encoding);
1528
1529         strbuf_init(&buffer, 8192); /* should avoid reallocs for the headers */
1530         strbuf_addf(&buffer, "tree %s\n", oid_to_hex(tree));
1531
1532         /*
1533          * NOTE! This ordering means that the same exact tree merged with a
1534          * different order of parents will be a _different_ changeset even
1535          * if everything else stays the same.
1536          */
1537         while (parents) {
1538                 struct commit *parent = pop_commit(&parents);
1539                 strbuf_addf(&buffer, "parent %s\n",
1540                             oid_to_hex(&parent->object.oid));
1541         }
1542
1543         /* Person/date information */
1544         if (!author)
1545                 author = git_author_info(IDENT_STRICT);
1546         strbuf_addf(&buffer, "author %s\n", author);
1547         if (!committer)
1548                 committer = git_committer_info(IDENT_STRICT);
1549         strbuf_addf(&buffer, "committer %s\n", committer);
1550         if (!encoding_is_utf8)
1551                 strbuf_addf(&buffer, "encoding %s\n", git_commit_encoding);
1552
1553         while (extra) {
1554                 add_extra_header(&buffer, extra);
1555                 extra = extra->next;
1556         }
1557         strbuf_addch(&buffer, '\n');
1558
1559         /* And add the comment */
1560         strbuf_add(&buffer, msg, msg_len);
1561
1562         /* And check the encoding */
1563         if (encoding_is_utf8 && !verify_utf8(&buffer))
1564                 fprintf(stderr, _(commit_utf8_warn));
1565
1566         if (sign_commit && sign_with_header(&buffer, sign_commit)) {
1567                 result = -1;
1568                 goto out;
1569         }
1570
1571         result = write_object_file(buffer.buf, buffer.len, commit_type, ret);
1572 out:
1573         strbuf_release(&buffer);
1574         return result;
1575 }
1576
1577 define_commit_slab(merge_desc_slab, struct merge_remote_desc *);
1578 static struct merge_desc_slab merge_desc_slab = COMMIT_SLAB_INIT(1, merge_desc_slab);
1579
1580 struct merge_remote_desc *merge_remote_util(struct commit *commit)
1581 {
1582         return *merge_desc_slab_at(&merge_desc_slab, commit);
1583 }
1584
1585 void set_merge_remote_desc(struct commit *commit,
1586                            const char *name, struct object *obj)
1587 {
1588         struct merge_remote_desc *desc;
1589         FLEX_ALLOC_STR(desc, name, name);
1590         desc->obj = obj;
1591         *merge_desc_slab_at(&merge_desc_slab, commit) = desc;
1592 }
1593
1594 struct commit *get_merge_parent(const char *name)
1595 {
1596         struct object *obj;
1597         struct commit *commit;
1598         struct object_id oid;
1599         if (get_oid(name, &oid))
1600                 return NULL;
1601         obj = parse_object(the_repository, &oid);
1602         commit = (struct commit *)peel_to_type(name, 0, obj, OBJ_COMMIT);
1603         if (commit && !merge_remote_util(commit))
1604                 set_merge_remote_desc(commit, name, obj);
1605         return commit;
1606 }
1607
1608 /*
1609  * Append a commit to the end of the commit_list.
1610  *
1611  * next starts by pointing to the variable that holds the head of an
1612  * empty commit_list, and is updated to point to the "next" field of
1613  * the last item on the list as new commits are appended.
1614  *
1615  * Usage example:
1616  *
1617  *     struct commit_list *list;
1618  *     struct commit_list **next = &list;
1619  *
1620  *     next = commit_list_append(c1, next);
1621  *     next = commit_list_append(c2, next);
1622  *     assert(commit_list_count(list) == 2);
1623  *     return list;
1624  */
1625 struct commit_list **commit_list_append(struct commit *commit,
1626                                         struct commit_list **next)
1627 {
1628         struct commit_list *new_commit = xmalloc(sizeof(struct commit_list));
1629         new_commit->item = commit;
1630         *next = new_commit;
1631         new_commit->next = NULL;
1632         return &new_commit->next;
1633 }
1634
1635 const char *find_header_mem(const char *msg, size_t len,
1636                         const char *key, size_t *out_len)
1637 {
1638         int key_len = strlen(key);
1639         const char *line = msg;
1640
1641         /*
1642          * NEEDSWORK: It's possible for strchrnul() to scan beyond the range
1643          * given by len. However, current callers are safe because they compute
1644          * len by scanning a NUL-terminated block of memory starting at msg.
1645          * Nonetheless, it would be better to ensure the function does not look
1646          * at msg beyond the len provided by the caller.
1647          */
1648         while (line && line < msg + len) {
1649                 const char *eol = strchrnul(line, '\n');
1650
1651                 if (line == eol)
1652                         return NULL;
1653
1654                 if (eol - line > key_len &&
1655                     !strncmp(line, key, key_len) &&
1656                     line[key_len] == ' ') {
1657                         *out_len = eol - line - key_len - 1;
1658                         return line + key_len + 1;
1659                 }
1660                 line = *eol ? eol + 1 : NULL;
1661         }
1662         return NULL;
1663 }
1664
1665 const char *find_commit_header(const char *msg, const char *key, size_t *out_len)
1666 {
1667         return find_header_mem(msg, strlen(msg), key, out_len);
1668 }
1669 /*
1670  * Inspect the given string and determine the true "end" of the log message, in
1671  * order to find where to put a new Signed-off-by trailer.  Ignored are
1672  * trailing comment lines and blank lines.  To support "git commit -s
1673  * --amend" on an existing commit, we also ignore "Conflicts:".  To
1674  * support "git commit -v", we truncate at cut lines.
1675  *
1676  * Returns the number of bytes from the tail to ignore, to be fed as
1677  * the second parameter to append_signoff().
1678  */
1679 size_t ignore_non_trailer(const char *buf, size_t len)
1680 {
1681         size_t boc = 0;
1682         size_t bol = 0;
1683         int in_old_conflicts_block = 0;
1684         size_t cutoff = wt_status_locate_end(buf, len);
1685
1686         while (bol < cutoff) {
1687                 const char *next_line = memchr(buf + bol, '\n', len - bol);
1688
1689                 if (!next_line)
1690                         next_line = buf + len;
1691                 else
1692                         next_line++;
1693
1694                 if (buf[bol] == comment_line_char || buf[bol] == '\n') {
1695                         /* is this the first of the run of comments? */
1696                         if (!boc)
1697                                 boc = bol;
1698                         /* otherwise, it is just continuing */
1699                 } else if (starts_with(buf + bol, "Conflicts:\n")) {
1700                         in_old_conflicts_block = 1;
1701                         if (!boc)
1702                                 boc = bol;
1703                 } else if (in_old_conflicts_block && buf[bol] == '\t') {
1704                         ; /* a pathname in the conflicts block */
1705                 } else if (boc) {
1706                         /* the previous was not trailing comment */
1707                         boc = 0;
1708                         in_old_conflicts_block = 0;
1709                 }
1710                 bol = next_line - buf;
1711         }
1712         return boc ? len - boc : len - cutoff;
1713 }
1714
1715 int run_commit_hook(int editor_is_used, const char *index_file,
1716                     const char *name, ...)
1717 {
1718         struct run_hooks_opt opt = RUN_HOOKS_OPT_INIT;
1719         va_list args;
1720         const char *arg;
1721
1722         strvec_pushf(&opt.env, "GIT_INDEX_FILE=%s", index_file);
1723
1724         /*
1725          * Let the hook know that no editor will be launched.
1726          */
1727         if (!editor_is_used)
1728                 strvec_push(&opt.env, "GIT_EDITOR=:");
1729
1730         va_start(args, name);
1731         while ((arg = va_arg(args, const char *)))
1732                 strvec_push(&opt.args, arg);
1733         va_end(args);
1734
1735         return run_hooks_opt(name, &opt);
1736 }